Caulking gun



United States Patent CAULKING GUN William A. Sherbondy, Pepper Pike, Ohio Application September 1, 1955, Serial No. 532,087

4 Claims. or. 222-327 i This invention relates to dispensers from which a compressible viscous fluid is displaced bya piston and more specifically this invention relates, as indicated, to caulking s 1 The fluids generally dispensed by a device of this type often contain substantialquantities of air. For this reason and also because the high viscosity of the fluid necessitates a substantial pressure thereon to force it from the dispenser nozzle, the fluid in the dispenser is slightly compressed during the period when any substantial quantity of it is forced through the nozzle or dispensing spout. When extrusion of the fluid from the dispenser'is no longer desired and the force is no longer applied to the piston in the dispenser, the fluid will tend to expand;

In the fluid dispensers of this type previously known to the art, the sliding fit, between the peripheryof the piston and the wall of the cardboard dispenser tube was very tight to prevent leakage and the-face of the piston was inflexible. Therefore, the expanding fluid, not being-able to move the piston rearward, simply oozed from the delivery nozzle of the cartridge, whenthe'gun was llaidaside after use.

It is, therefore, a primary object of this'inventionv to provide a piston for fluid dispensers wherein a portion of the fluid-engaging face of the piston is movable rearwardly away from the nozzle when the actuating force on the piston is relieved.

It is a more specific object of this invention to provide a piston for dispensers of this type wherein pressure on the fluid in the dispenser may cause the fluid chamber to expand Without overcoming the friction between the periphery of the piston and the wall of the dispenser.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail an illustrative embodiment of the invention, this being indicative, however, of but one of the various ways in which the principle of the invention may be employed.

In the annexed drawings:

Fig. 1 is a side elevational view partially in section of the preferred form of my invention wherein the parts are illustrated in their delivery position;

Fig. 2 is an enlarged cross-sectional view of the apparatus illustrated in Fig. 1 wherein the parts are shown in their non-delivery position; and

Fig. 3 is an enlarged fragmentary view of the piston illustrated in Figs. 1 and 2.

Broadly stated, my invention comprises in a caulking gun assembly wherein a piston member is movable axially in a cylindrical cartridge to force the contents therefrom through a discharge nozzle and such piston is thus moved axially in said cartridge by an axially reciprocable mem- 2,778,541 Patented Jan. 22, 1957 her having ahead engageable with such piston, the improvement comprising the provision in said piston, centrally thereof, a portion which will deflect toward the nozzle end'of the gun when pressure is applied to said piston by said head and which will deflect in the opposite direction when the contents of the gun exert a back pressure on said piston when the pressure of said head on said piston is relieved.

With reference now to the annexed drawing, 9 designates the cylindrical wall of a caulking gun; 10 designates the wall of a cartridge therein;11 designates the gun handle; 12 designates the trigger by which the piston in the cartridge is actuated, and 13 designates the nozzle of the gun. A rod 14 is provided coaxial with the cylinder 9 and extending into the cartridge 10 and the cylinder 9. The rod 14 is provided with a plurality of notches 15 which cooperate with driving and holding pawls ,(not shown) associated with the trigger 12 and handle 11 respectively so as to incrementally axially advance the rod 14 toward the left each time that the trigger 12 is pulled toward the right. On the internal end of the rod 14 there is provided a plunger 16 which has a convex head 17. Slidably mounted in the cartridge 10 is a piston generally indicated at 18 in Fig. 1 and illustrated in greater detail in Figs. 2 and 3.. The piston 18 comprises a cylindrical member19 having a radially inwardly extending flange 20,-a flexible diaphragm 21, and a cylindrical member 22 having a radially inwardly extending flange 23, the member 22: being adapted to secure the periphery of the diaphragm 21 against the member 19. A i I When this form of my invention is used to deliver a viscous compressible fluid, indicated at 24 in Figs. 1 and 2, through the nozzle 13, the trigger 12 is pulled toward the handle 11 whereby the rod 14 is axially advanced into the cartridge 10. As the head 16 approaches the piston 18*the convexhead 17 of the plunger 16 will enter the piston 18inside the flanges 20 and -23and contact the diaphragm 21 forcing it into the body 24 of fluid. To insure that the plunger 16 does not rupture the diaphragm 18, a flanged portion 25 of the plunger 16 contacts the flange 23 so that further axial movement of the plunger 16 insures positive displacement of the piston 18. It is desirable that the convex head 17 of the plunger 16 have the shape of a compound curve as illustrated in Figs. 1 and 2 in order that the radially outward portion of the plunger 16 will enter the piston 18 soon enough after the central portion 17 does so that undue stresses on the diaphragm 21 are avoided. Further actuation of the trigger 12 will effect displacement of the piston 18 toward the nozzle 13 so that the fluid in the cartridge 10 is compressed and then forced rapidly through the nozzle 13. When it is desirable to discontinue extrusion of the fluid from the nozzle 13, the rod 14 is rotated about its longitudinal axis about or more so that the ratchet mechanism in the handle 11 and trigger 12 is disengaged from the notches 15. The rod 14 is then free to be moved axially outward of the cartridge 10 under the influence of the pressure of the compressed fluid 24 acting on the diaphragm 21 and on the head 16 of rod 14 whereby the fluid 24 expands within cartridge 10 without oozing from the nozzle 13.

In the form of the invention herein disclosed, it has been found desirable to provide for about A total deflecting movement of the center portion of the diaphragm 21 in a cartridge 10 of 2" diameter and when the cartridge is nearly full. Of course, such /1 deflection is not needed when the cartridge is nearly empty.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, orthe equivalent of such, be employed;

I, therefore, particularly point out and distinctly claim as my invention: 1. A pistonfo'r'use in'a caulking gun wherein a piston is movable axially'in"a'cylindrical-c'ohtainer to force the contents therefrom through a discharge nozzle and such piston'is thus moved'to'imposepressure' o'n'such contents by an axially'recip'rocable member, said p'iston'comprising arigidannu'lusincludingan outer'p'art of such configuration as to fit tightly within such container and an inner part telescoped within said outer part, and a film of ilexible'material having a'periph'eral portion clamped between said outer and inner parts of said rigid annulus and aresilien't center" portion that is axially displaceable with respect to's'aid annulus by the back pressure of such contents upon release of" such impo'sed'p'ressure, whereby said contents may be compressed during the forcing thereof through said nozzle, but no extrusion of said contents through said nozzle takes place after the release of pressure upon said contents until pressure is again applied.

2. A caulking gun comprising a cylindrical container provided with a dispensing nozzle at one end and a piston fitted into the other end, and a cartridge support and piston actuator assembly provided with a reciprocable piston actuator which is engageable with said piston to axially move the latter into said container to force the contents therefrom through said nozzle, said piston comprising a rigid annulus including. an outer part having a skirt which has a-snug sliding fitin said container andan inner part having a'skirt telescoped within the skirt of the said outer part, and a film of flexible material having a peripheral portion gripped between the skirts of said'outer and inner parts of said annulus and a resilient center portion that is axially displaceable relative to said skirts by the back pressure of the contents upon release of piston-actuating force on said actuator, whereby said contents may be compressed during the forcing thereof through said nozzle, but no extrusion of said contents through said nozzle 4 takes place after the release of pressure upon said contentsuntil' ressure is again applied 3. The caulking gun of claim 2 wherein the center portion of said film is initially bulged convexly toward said actuator, and wherein said actuator is shaped to first engage such center portion to axially displace the latter relative to said annulus and then to engage said annulus to bodily move said piston in-said cartridge.

4. A piston for use in a caulking gun wherein a piston is movable axially in a cylindrical container to force the contents therefrom through adischarge nozzle and such piston is thus moved to impose pressure on such contents by an axially reciprocable member, said piston comprising a rigid annulus having a-nouter part of such configuration as to fit tightly within such container and an inner part telescoped within said outer part, and a film of flexible material having a peripheral portion clamped between said outer and inner parts of said rigid annulus and a resilient center portion that is axially displaceable with respect to said rigid annulus by the back pressure of such contents upon release of such imposed pressure, the center portion of said film being convexly bulged with respect to said peripheral portion-for facilitating initial axial displacement in one direction relative to said annulus under the influence of the axiallyreciprocable member and for axial displacement in the opposite direction relative to said annulus by the back pressure of such contents upon release of the imposed pressure, whereby said contents may be compressed during the forcing thereof through said nozzle, but no extrusion of said contents through said nozzle takes place after the release of pressure upon said contents until pressure is again applied.

ReferencesCitedin'the file of this patent UNITED STATES PATENTS 1,270,835 Jersemann July 2, 1918 2,098,524 Smith Nov. 9, 1937 2,111,582 Crewe Mar. 22, 1938 2,371,332 Jacobson Mar. 13, 1945 2,430,718' Jacobson Nov. 11, 1947 

